In recent years, services using the Internet have continuously increased. In an operation system that manages these services, due to a characteristic of the Internet that it is “accessible at anytime at any place”, a demand on the operation system for resources fluctuates widely. As a result, when resources (for example, server resources) of the operation system are prepared to meet a peak of demands (when the requirement amount is maximal), the capacity is in surplus in normal times (when the requirement amount is average), and a facility is wasted. Meanwhile, when resources of the operation system are prepared according to the normal requirement amount, there would not be a sufficient capacity at the peak of the demands. As a result, a business opportunity may be lost.
In order to solve the above problem, studies have been made on a utility computing (UC) technology (or Capacity on Demand (CoD) technology) for dynamically optimizing the resources of the operation system according to changing demand on the operation system.
A conventional UC technology will be described by way of example with reference to FIG. 18. FIG. 18 is a block diagram illustrating the conventional UC technology. As illustrated in FIG. 18, an Internet Data Center (hereinafter, simply referred to as IDC) using the UC technology includes an IDC managing device that manages the IDC using the UC technology (for example, allocates each server of the IDC to each customer device), a customer device (system of an IDC user) that is operated by each customer using the IDC, and a server pool that includes resources of the server managed by the IDC managing device and not allocated to any of the customer devices. Each of the customer devices includes a service providing unit that provides a service and a system managing unit that manages a system, and provides a service of each customer to an end user through a network.
Next, a relationship between the IDC, the IDC managing device, the customer, and the end user will be described. The IDC managing device provides resources of the IDC to each customer device. The IDC managing device offers each customer device resources for providing services (for example, the IDC managing device offers the customer device a server as a server for providing services, and the customer device also requests the IDC to manage the operation of the offered server itself), and the customer device provides a corresponding service of each customer to the end user. The end user is a user who receives the service provided by each customer. In actuality, the end user has access to the IDC (for example, server of the IDC) and receives the service of each customer.
The IDC managing device offers each customer device resources of servers in two different manners. Firstly, the IDC managing device offers the resources of the server as fixed resources. Here, the fixed resources are resources that are previously allocated to each customer device and provided thereto constantly. For example, in a common method, the amount of resources that are allocated as the fixed resources is determined according to a contract between each customer and the IDC, and the IDC managing device allocates the fixed resources to each customer set in advance constantly, even when the requirement amount (the amount of resources used by the end user in actuality) of the customer device is less than the fixed resources.
Secondly, the IDC managing device provides resources of the server as spare resources (on-demand resources). The spare resources are resources that are temporarily allocated to each resource-shortage customer device aside from the fixed resources; the resource-shortage customer device is a customer device for which the previously allocated fixed resource becomes temporarily insufficient. For example, when the requirement amount of each customer device increases or when the fixed resources previously allocated to each customer device become defective, and the customer device cannot operate only with the fixed resources, the spare resources is allocated in addition. In a common method, yet-allocated fixed resources are used as the spare resources; the yet-allocated fixed resources are resources of a server which have not been allocated to any of the customer devices as the fixed resources. The spare resources are allocated to each resource-shortage customer device by a required amount, when necessary, and are returned to a shared pool, when they become unnecessary.
For example, Japanese Laid-open Patent Publication No. 2004-326452 (refer to pages 1, 5, and 14 to 17 and FIG. 1) discloses a method according to which remaining fixed resources, that is, non-used resources among fixed resources allocated to each customer device are borrowed and lent between the customer devices.
Specifically, a customer (lending customer) who provides the remaining fixed resources to the IDC registers the remaining fixed resources it can lend in the IDC managing device. The IDC managing device receives a request from a customer (borrowing customer) who requests for the spare resources, and provides the lendable, remaining fixed resources of the lending customer to the borrowing customer. During this exchanging process, the borrowing customer pays a charge for using the spare resources (remaining fixed resources) and the lending customer receives a charge according to an actual record of the lent remaining fixed resources, from the IDC managing device.
According to the above-described conventional technology, however, the resources cannot be appropriately allocated as described below.
For example, the conventional technologies and Japanese Laid-open Patent Publication No. 2004-326452 do not disclose how to determine which resources among lendable resources are to be allocated to the borrowing customer when the borrowing customer makes a request for the spare resources, and hence the resources cannot be allocated efficiently.
Specifically, Japanese Laid-open Patent Publication No. 2004-326452 does not take into account a time for assigning an application to the resources of the server provided to each customer device for providing a service when the spare resources are lent. In addition, each borrowing customer may not be able to provide a service in a desirable time zone during which the borrowing customer wants to use the spare resources to provide a service, if using a time zone allocated by the IDC managing device to the borrowing customer.
In addition, in the conventional technologies, the lending customer cannot immediately receive the return of the lent fixed resources. For example, while the fixed resources is lent out, the lending customer may desire that the borrowing customer immediately return the lent fixed resources due to non-predictable, abrupt generation of load; however, the lending customer cannot receive the return of the fixed resources immediately.